Methods and devices for estimating a component transmission loss of radar signal

ABSTRACT

Methods and devices for estimating a component transmission loss are provided. In an exemplary embodiment, a method includes receiving a desired substrate criterion of a desired substrate, and receiving a desired coating criterion of a desired coating. A component includes the desired substrate and the desired coating. A coating criterion value is received, where the coating criterion value quantifies the desired coating criterion. A desired coating permittivity is estimated for the desired coating, using the coating criterion value, and an estimated component transmission loss of radar signal through the component is produced.

TECHNICAL FIELD

The technical field relates to methods and devices for estimating radarsignal transmission and more particularly relates to methods and devicesfor estimating transmission loss of radar signal through a component.

BACKGROUND

Radar is used in motor vehicles to detect objects for a variety ofpurposes, such as autonomous driving and automatic braking. The radar istypically mounted behind a component of the motor vehicle, typically abumper or vehicle panel, so the component covers the radar device. Inthis regard, the radar signal must penetrate the bumper when travelingto an object to be detected, and then penetrate the bumper again whenreflected off of the object and returning to the vehicle. The bumper,including any coatings applied to the surface of the bumper, cantransmit, reflect, or absorb radar. Any reflection or absorption of theradar signal limits the effective detection range of the radar. For theradar to be useful for automatic braking, the effective range of theradar must be at least as far as the braking distance of the vehicle atthe driving speed.

If the component, e.g., the bumper or vehicle panel, behind which theradar is mounted is metal, the effective range of the radar is zero, sothe components utilized are typically plastic or other non-metallicmaterials. The component includes the substrate, but also typicallyincludes a coating overlying the substrate. Motor vehicle coatingstypically include a basecoat, and often also include a primer coatand/or a clearcoat, with an interface between each layer. The radartypically used in motor vehicles for detecting objects is 77 giga hertz(GHz) brand radar, which describes a category of radar that includesfrequencies from about 76 to 81 GHz.

The frequency band of about 76-81 GHz corresponds to a wavelength rangeof about 3.70 to about 3.94 mm. The radar waves are roughly on the samelength scale as the bumper or panel that covers the radar device, so theradar signal travelling through the coated bumper or panel cover issubject to a phenomenon known as interference. Interference affectssignal transmission due to the interactions of reflected signals thatoccur at the front and rear sides of the bumper cover. The reflectedwaves from the two surfaces can interact constructively, increasing thereflection, or destructively, subsequently decreasing the reflection.Signal transmission can be improved by tuning the bumper and coatingthickness to achieve destructive interference.

The transmission of a radar signal through a typical bumper substrateand the coating layers thereon can be significantly changed by minorvariations, where a reduction of reflection and absorption results in anincrease in transmission (i.e., lower transmission losses). The type ofmaterial in the substrate, the type of coating layers, the components inthe coating layers, and the thickness of the coating layers allinfluence the transmission. It is possible to optimize the substrate andcoating layers to reduce the effects of reflection losses due toconstructive interference. Calculation of the reflection andtransmission of a multilayer system can be performed if the complexpermittivity properties and thickness values are known for allconstituent layers.

Accordingly, it is desirable to develop methods and devices toaccurately estimate the transmission of a substrate and coatings to aradar signal. Furthermore, it is desirable to develop methods anddevices to recommend modifications to selected substrate and coatingcombinations that result in decreased transmission losses, and toestimate the transmission losses for those modifications. Furthermore,other desirable features and characteristics will become apparent fromthe subsequent detailed description and the appended claims, taken inconjunction with the accompanying drawings and the foregoing technicalfield and background.

SUMMARY

Methods and devices for estimating a component transmission loss areprovided. In an exemplary embodiment, a method includes receiving adesired substrate criterion of a desired substrate, and receiving adesired coating criterion of a desired coating. A component includes thedesired substrate and the desired coating. A coating criterion value isreceived, where the coating criterion value quantifies the desiredcoating criterion. A desired coating permittivity is estimated for thedesired coating, using the coating criterion value, and an estimatedcomponent transmission loss of radar signal through the component isproduced.

A method for estimating a component transmission loss is provided inanother embodiment. The method includes receiving a desired substratecriterion of a desired substrate, a desired coating criterion of adesired coating, and a coating criterion value that quantifies thedesired coating criterion. A motor vehicle component includes thedesired substrate and the desired coating. A desired coatingpermittivity for the desired coating is estimated with the coatingcriterion value, and an estimated component transmission of radar signalthrough the component is determined. It is then determined if theestimated component transmission loss is less than a maximum componenttransmission loss. A recommended criterion is suggested if the estimatedcomponent transmission loss is greater than the maximum componenttransmission loss, where the recommended criterion reduces the estimatedcomponent transmission loss to less than the maximum componenttransmission loss, and where the recommended criterion is a substratecriterion, a coating criterion, or both.

A device for estimating a component transmission loss is provided in yetanother embodiment. The device includes a computer readable mediumembodying a computer program. The computer program is configured toreceive a desired substrate criterion of a desired substrate, andreceive a desired coating criterion of a desired coating, where acomponent includes the desired substrate and the desired coating. Acoating criterion value is received, where the coating criterion valuequantifies the desired coating criterion. A desired coating permittivityfor the desired coating is estimated with the coating criterion value,and an estimated component transmission loss of radar signal through thecomponent is produced.

DESCRIPTION OF THE DRAWINGS

The exemplary embodiments will hereinafter be described in conjunctionwith the following drawing figures, wherein like numerals denote likeelements, and wherein:

FIG. 1 is a perspective sectional view of an embodiment of a component;

FIG. 2 is a flow chart a method for determining an estimated componenttransmission loss of radar signal, according to an exemplary embodiment;

FIG. 3 is an exemplary graph of the weight percent of an exemplaryeffect pigment in a dry coating film vs. the permittivity of that drycoating film;

FIG. 4 is a graph of the transmission loss of radar signal of anexemplary component plotted against a radar signal frequency;

FIG. 5 is a flow chart of a step of the method of FIG. 2 , in accordancewith an exemplary embodiment;

FIG. 6 is a three-dimensional graph of the transmission loss plottedagainst a desired substrate thickness and a basecoat permittivity; and

FIG. 7 is a schematic diagram of a computer that may be used toimplement the method of estimating a component transmission loss ofradar signal, in accordance with an exemplary embodiment.

DETAILED DESCRIPTION

The following detailed description is merely exemplary in nature and isnot intended to limit the application and uses. Furthermore, there is nointention to be bound by any expressed or implied theory presented inthe preceding technical field, background, brief summary or thefollowing detailed description.

A vehicle “component,” as used herein, includes a plastic or polymericsubstrate with an overlying coating. The term “overlying,” as usedherein, means the overlying material may be physically touching theunderlying substrate, or the overlying material may be physicallyseparated from the underlying substrate by an intervening material, suchas an overlying clearcoat that may be separated from an underlyingsubstrate by a basecoat. It is understood that a component may berotated or moved, so reference to one component overlying another refersto the orientation in the FIGS., with the understanding that the actualcomponent may be rotated into a different orientation. The term“vehicle,” as used herein, refers to a motor vehicle, such as a car,truck, airplane, or other device propelled through space with a motor orengine. The term vehicle includes vehicles propelled by a motor burningfuel for power, and a vehicle propelled by an engine using electricity.The overlying coating of the component includes one or more of a primer,a basecoat, and a clearcoat.

Techniques for estimating a transmission loss of radar signal through atheoretical component are described, where the transmission losses canbe estimated without the need to actually manufacture the component andtest it. As such, the composition of the component can be varied toprovide a design that limits the transmission loss to a less than orequal to a maximum transmission loss, and then a physical version of thecomponent may be produced. It has been discovered that many factorsinfluence the transmission loss of radar signal through a component inunexpected ways. For example, in some cases the transmission loss can bereduced by producing thicker layers of the substrate and/or one or moreof the layers of the coating. Also, changes to the pigment loading inthe coating may have a significant influence, where some pigments have amuch greater influence on the transmission loss than others. Othercomponents of the coating may also influence the transmission loss. Forexample, adhesion promotors in the primer layer may influence thetransmission loss, where different concentrations and different types ofadhesion promotors have different levels of influence.

Referring to FIG. 1 , an exemplary desired component 30 is shown. Thedesired component 30 may not be tangible, because it is onlytheoretical, but the illustration simplifies the understanding of thedesired component 30. Furthermore, the desired component 30 may bephysically produced in some embodiments, so all the features of thedesired component 30 may be duplicated in a real, tangible component.The desired component 30 includes a desired substrate 32 and a desiredcoating 34, where the desired coating 34 includes one or more of adesired primer 36, a desired basecoat 38, and a desired clearcoat 40.The desired substrate 32 and desired coating 34 have several criteriathat represent physical aspects of the desired substrate 32 and desiredcoating 34, and these criteria are referred to herein as “desired”criteria when used to describe the desired substrate 32 and/or thedesired coating 34. The desired substrate 32 has some desired substratecriteria, such as a desired substrate material, a desired substratethickness 42, and optionally other possibilities such one or moredesired substrate additives, or a desired shape. For example, thedesired substrate material may be polypropylene, polycarbonate, amixture of polycarbonate and ABS plastic with a specified concentrationof polycarbonate and ABS plastic, fiberglass with a specified type ofresin, carbon fiber with a specified type of resin, polyethylene,layered polypropylene and polyethylene with specified thicknesses foreach layer, homogeneous and heterogeneous polymer mineral mixtures andcomposites, etc.

The desired coating 34 includes several possible desired coatingcriteria. For example, a desired coating thickness 44 is a sum of adesired primer thickness 46, a desired basecoat thickness 48, and adesired clearcoat thickness 50. Any of the desired primer, basecoat, orclearcoat 36, 38, 40 may be applied with one, two, or more layers, each.For example, if the desired clearcoat 36 is applied in two layers, thecombined two layers may be considered the desired clearcoat 36. Otheroptional coating layers may also be present in some embodiments, such asa sealer, surfacer, adhesion promotor, midcoat, etc. The desiredbasecoat 38 includes a desired pigment 52, which is illustrated in FIG.1 as effect pigment flakes. There may be more than one desired pigment52 in some embodiments, such as effect pigment flakes, interferenceflakes, colored pigments, etc. Furthermore, the desired pigment 52 maybe further described with additional, optional desired coating criteria,such as effect pigment flakes that are colored, effect pigment flakeswith varying aspect ratios, effect pigment flakes with physical vapordeposited coatings, thin-milled flakes, achromic and chromatic micas andglass flakes, etc.

Other variations on the desired coating criteria include the optionalpresence of an adhesion promotor in the primer and/or the basecoat, thetype of adhesion promotor, the concentration of the adhesion promotor,etc. Various conductive additives may also be included in one or more ofthe desired primer, basecoat, and clearcoat 36, 38, 40 as a coatingcriterion, where the conductive additive may be present at varyingconcentrations. Another potential desired coating criterion includes thetype of resin in one or more of the desired primer, basecoat, andclearcoat 36, 38, 30, such as acrylic resin, epoxy resin, polyurethaneresin, etc. The number of variables potentially influencing thetransmission loss of the desired component 30 is large. The transmissionloss in the FIGS. is shown as a negative decibels value, where a valueof 0 decibels indicates no transmission loss. Therefore, the further avalue is from 0, the greater the transmission loss, where greatertransmission loss indicates reduced radar power penetrating the desiredcomponent 30.

A method 58 of estimating a component transmission loss of radar signalis illustrated in FIG. 2 , with continuing reference to FIG. 1 . Themethod includes the steps of receiving a desired substrate criterion 60,and receiving a desired coating criterion 62. In an exemplaryembodiment, a user selects the various criterion, and a computerreceives the selected items. The desired substrate criterion may includemore than one desired substrate criterion. For example, the step ofreceiving a desired substrate criterion 60 may include receiving amulti-layer desired substrate 32 where the composition and thickness ofeach layer is received. Alternatively, the composition and a percent ofthe total thickness of each layer may be received. In anotherembodiment, a composition may be received without the associated desiredsubstrate thickness 42. A default desired substrate criterion may alsobe provided, such that when a desired substrate criterion is notreceived, a default selection of the desired substrate criterion isprovided, such as the substrate composition is polypropylene in anexemplary embodiment. Other default criteria may be utilized inalternate embodiments.

The step of receiving a desired coating criterion 62 may includereceiving one or several desired coating criterion. For example, thethickness of each layer may be received, where the thickness of a layerthat is not received may default to a value of zero (0). Also, thedesired pigment(s) 52 may be received, and a user may provide thedesired pigment(s) 52 and the desired basecoat thickness 48 withconsiderations such as how well the desired basecoat 38 will hide theunderlying layers. The desired primer, basecoat, and clearcoat thickness44, 46, 48 may be thickness when the respective layers are dried, but awet layer thickness could be used in alternate embodiments. A computerprogram or other device may request information from a user, so that theuser provides the information that is received by the computer.

Once the desired coating criterion is received 62, a coating criterionvalue is received that quantifies the desired coating criterion 63. Thedesired substrate criterion may also be quantified in some embodiments,but in alternate embodiments the desired substrate criterion may not bequantified. The coating criterion value is a quantification of thedesired coating criterion with a measurable value. For example, thecoating criterion value may be the desired basecoat thickness 48, whichcan be measured to provide a specific coating criterion value. In analternate embodiment, the coating criterion value may be aconcentration, such as the concentration of the desired pigment 52 inthe desired basecoat 40. A selection of a type of resin, such as anacrylic resin, is not quantifiable. However, the concentration of thatresin in a dried coating layer can be quantified. A user may provide thecoating criterion value. Also, receiving the coating criterion value toquantify the desired coating criterion 63 may include receiving morethan one coating criterion value for more than one desired coatingcriterion.

Once the desired coating criterion is received, and the desired coatingcriterion is quantified with a coating criteria value, a desired coatingpermittivity is estimated for the desired coating 64. In an exemplaryembodiment, a computer estimates the permittivity, where the coatingcriteria value is an input into the estimation. Models may be made foreach desired coating criterion, based on actual testing data forphysical samples, and a computer may use the models to estimate thedesired coating permittivity.

For example, for each potential desired coating criterion, a pluralityof physical samples with a plurality of known criteria values may beproduced for each desired coating criterion, where the plurality ofknown criteria values are varied and all other coating parameters areheld constant. A known coating permittivity can then be physicallymeasured for each sample, and a mathematical model or other estimationtechnique may be produced that relates the plurality of known coatingpermittivities to the plurality of different known criteria values forthe desired coating criterion. Then, a desired coating criterion valuecan be entered into the mathematical model to estimate a desired coatingpermittivity. The influence of each potential desired coating criteriacan be weighted and combined to give a technique for estimating thedesired coating permittivity for the desired coating 64 using acombination of a plurality of different desired coating criteria and aplurality of different coating criteria values. The weighting or othertechniques for combining the influence of different desired coatingcriteria can be determined experimentally using representative examples,and a mathematical model may be produced that includes the influence ofdifferent desired coating permittivities on the estimated desiredcoating permittivity. This testing can then be included in themathematical models for estimating the desired coating permittivity ofthe desired coating 64. The same process may be used for a desiredcoating loss tangent of the desired coating. The desired coating losstangent may be determined with the desired coating permittivity, and inthis description the estimation and use of the desired coating losstangent, and the loss tangent for other layers, is not specificallydescribed but is included with discussions of the permittivity ortransmission loss described herein.

Referring to an exemplary embodiment illustrated in FIG. 3 , the weightpercent of effect pigment flakes in a dry basecoat was physicallyproduced and tested for permittivity, where the basecoat thickness,resin, and other factors were kept constant. It has been discovered thatthe presence of metal containing effect pigment flakes in the basecoathas a greater influence on the permittivity than many other possibledesired coating criteria, such as the type of resin used in any layer,the presence of other types of pigments, or the presence of a clearcoat.The points in FIG. 3 illustrate individual concentrations of effectpigment flakes in a dry film, where each measured concentration ofeffect pigment flakes is one of the plurality of different coatingcriterion values. The permittivity of the dry film was then measured foreach concentration of effect pigment flakes in the dry film.

A graph of the coating permittivity vs. the concentration of effectpigment flake in the basecoat was produced, and is illustrated in FIG. 3. This graph may aid in estimating the desired coating permittivity forthe desired coating 64. In one embodiment, a mathematical model of thepermittivity vs. the concentration of effect pigment flakes is produced,where the dotted line in FIG. 3 illustrates one example of a linearmathematical model. This mathematical model may then be used to estimatethe permittivity of the desired basecoat 38, and this permittivity maybe included in an estimate of the permittivity (or transmission loss) ofthe desired component 30. Other types of mathematical models may beutilized in alternate embodiments, such as exponential models. The typeof mathematical model used may vary from one desired coating criterionto the next, where the known values that are experimentally determinedmay serve as a guide for the technique used to estimate the desiredcoating permittivity. Some coating criteria may have little influence onthe estimated component transmission loss, so default values may beutilized. For example, for some types of resin, the desired clearcoatthickness 50 has little influence on the estimated componenttransmission loss.

Alternatively, the graph may be used directly for estimating the desiredcoating permittivity for the desired coating 64, such as interpolatingthe permittivity for the desired basecoat 38 from the values plotted inthe graph on FIG. 3 . In this exemplary embodiment, the concentration ofthe effect pigment flakes in the basecoat is the known coating criterionvalue, and this known coating criterion value is located along the “Y”axis of the graph in FIG. 3 . The permittivity of the desired basecoat38 may be estimated by using a weighted average of the measured knowncoating permittivities of the samples having an effect pigment flakeconcentration slightly greater and slightly less than that of thedesired basecoat 38. The interpolation may be performed mathematicallyin some embodiments.

Referring back to FIG. 2 , with continuing reference to FIG. 1 , anestimated component transmission loss of radar signal through thedesired component is produced 66 utilizing the desired substratecriterion that was received and the estimated desired coatingpermittivity for the desired coating 64. Different techniques may beutilized for determining the estimated component transmission loss ofradar signal through the desired component 66 in various embodiments.For example, the general transfer matrix method may be used in oneembodiment, the ray transfer matrix analysis may be used in anotherembodiment, and the transmission line method may be used in yet anotherembodiment. Alternate techniques may also be used in alternateembodiments. This analysis is described in many references, and thecalculations are understood by those skilled in the art. However, allmodels require a permittivity value for each layer. Therefore, theestimation of the desired coating permittivity for the desired coating64 is an important component in the determination of the estimatedcomponent transmission loss of radar signal through the desiredcomponent 66.

In an exemplary embodiment, a maximum component transmission loss isprovided, where the maximum component transmission loss is thetransmission loss that still permits the radar to detect an object at adistance greater than a stopping distance of the vehicle. Of course, themaximum component transmission loss may be calculated in differentmanners in alternate embodiments. For example, a maximum componenttransmission loss may be the transmission loss that still permits thedetection of an object within the maximum braking distance experiencedduring inclement weather conditions. The maximum component transmissionloss may serve different purposes in different embodiments. Once theestimated component transmission loss is determined, it may be comparedto the maximum component transmission loss to determine if the estimatedcomponent transmission loss is less than the maximum componenttransmission loss 68. This is a simple matter of determining whichnumber is smaller, the estimated component transmission loss or themaximum component transmission loss.

The estimated component transmission loss varies with different radarfrequencies. The radar typically used in motor vehicles for detectingobjects has a frequency ranging from about 76 to about 81 giga hertz(GHz), and radars of this frequency are sometimes referred to as “77GHz” radar. The term “77 GHz radar” does seem to indicate radar at afrequency of 77 GHz, but in the industry the term “77 GHz radar” isunderstood to refer to radar having a frequency ranging from about 76 toabout 81 GHz. In this disclosure, reference to “77 GHz brand radar” willrefer to radar with frequencies ranging from 76 to 81 GHz, and referenceto “77 GHz radar”, without the word “brand,” will refer to radar atabout 77 GHz. The frequency of 77 GHz brand radar can influence thetransmission loss, as illustrated in FIG. 4 . FIG. 4 illustrates thetransmission loss of radar signal for one exemplary desired component 30over a range of radar frequencies, where the lowest transmission loss isat a radar frequency of about 77 to 78 GHz. Referring to FIG. 2 , insome embodiments, the method 58 of estimating a component transmissionloss optionally includes the step of receiving a desired radar frequencyfor producing the estimated component transmission loss 70. However, insome embodiments, a default radar frequency is used. In yet anotherembodiment, a recommended radar frequency is suggested to reduce theestimated component transmission loss 71.

Referring still to FIG. 2 , with continued reference to FIGS. 1, 3, and4 , another optional step is illustrated. The method 58 includes thesteps 60, 62, 63, 64, and 66 described above, but the method may thensuggest a recommended criterion to produce a reduced estimated componenttransmission loss 72. Optional step 72 may be in place of step 68 andstep 71, or in addition to them. The method 58 includes one or more ofsteps 68, 71, and 72. The recommended criterion is a substratecriterion, a coating criterion, or both. For example, the method 58 maysuggest a change in the desired substrate thickness 42, or a change inthe desired basecoat thickness 48, or a change in the desired radarfrequency (as specifically mentioned above), or a change in the desiredbasecoat pigment loading, or even a combination of the above. Therecommended criterion is one or more of the potential substrate criteriaand/or the potential coating criteria, where the recommended criterionmay or may not be the desired substrate criterion or the desired coatingcriterion originally received. This provides an alternate method toprovide an estimated component transmission loss of radar signal, andaids in the development and design of a vehicle component with reducedcomponent transmission loss. In an exemplary embodiment, the suggestionof a recommended criterion is made if the estimated componenttransmission loss is greater than the maximum component transmissionloss, and the recommended criterion reduces the estimated componenttransmission loss to a value less than the maximum componenttransmission loss.

Some examples of suggesting a change in a recommended criterion toproduce a reduced estimated component transmission loss 72 areillustrated in FIG. 5 , with continuing reference to FIGS. 1-4 . Step 72may include suggesting a desired substrate thickness to reduce thedesired component transmission loss 74. Alternatively, or in addition,step 72 may include producing a graph illustrating the estimatedcomponent transmission loss against a substrate criterion 76. Stillanother embodiment of step 72 includes producing a graph illustratingthe estimated component transmission loss against a coating criterion78. Combinations of different charts, graphs, or suggestions are alsopossible in some embodiments. The graph(s) described above may be atypical two-dimensional graph, but in some embodiments the graph may bea three-dimensional graph, as illustrate in FIG. 6 . The flat plane inFIG. 6 at a transmission loss of about −0.5 decibels represents anexample of the maximum component transmission loss, and this may or maynot be present in the graphs described above. The curve illustrated inFIG. 6 illustrates how increases in the desired substrate thickness 42can actually reduce the desired component transmission loss, where theestimated component transmission loss has minimum values at a desiredsubstrate thickness of about 2.3 millimeters (mm), and about 3.6 mm, butthe estimated component transmission loss is much higher at about 3 mm.

Step 72 may alternatively suggest a recommended criterion, and this maybe done without the use of the graphs described above. The graphsdescribed above, and the exemplary embodiment in FIG. 6 , are onetechnique of suggesting a recommended criterion to reduce thetransmission loss of a desired component 72, but other techniques ofsuggesting a recommended criterion may also be utilized. For example,the suggestion of a recommended criterion may be a simple textual oraudible suggestion. In some embodiments, the suggestion of a recommendedcriterion may include a suggestion of more than one recommendedcriterion, such as a recommended desired substrate thickness 42 to anoptimal level and a recommended desired basecoat thickness 48. A widevariety of suggestions for various recommended criteria may be employedin various embodiments, including suggestions of more than onerecommended criterion at a time, either with or without a graph.

The design of an actual component may be based on the various desiredcriteria described herein, so the desired coating criterion and thedesired substrate criterion may be implemented into an actual coatingcriterion and an actual substrate criterion. The methods described aboveallow the design of an actual component with a low transmission loss ofradar signal.

Referring to FIG. 7 , a computer 10 may be used as a device to implementthe techniques and methods described herein. The computer 10 may includean input device 12, such as a keyboard 14, a mouse 16, electroniccommunication devices such as a modem, or a variety of othercommunication devices. The input device 12 communicates with aprocessing unit 18 and/or a memory 20 of the computer, where theprocessing unit 18 and the memory 20 communicate with each other. A widevariety of processing unit 18 and memory 20 embodiments are known tothose skilled in the art. The computer 10 also includes an output device22, such as the monitor illustrated. Other exemplary embodiments of anoutput device 22 include a modem, a printer, or other components knownto those skilled in the art. The methods and techniques described abovemay be implemented on the computer 10.

A computer readable medium 24 embodies a computer program, where thecomputer program directs the computer to implement the method andtechniques described above. The computer readable medium may be an SDcard, a USB storage medium, a floppy disk, a CD-ROM, a DVD, a harddrive, or other devices that are readable by a computer, and thatinclude memory for saving the computer program. In some embodiments, thecomputer program may be electronically downloaded to the computer, butthe downloaded computer program is saved on a tangible device somewhere.

In an exemplary embodiment, the computer program directs the computer torequest input from the input device 12, wherein the requested inputincludes the desired substrate criterion, the desired coating criterion,and the coating criterion value that are received. The computer programdirects the processing unit 18 to estimate the desired coatingpermittivity for the desired coating, where the processing unit 18 mayaccess the mathematical model for estimating the desired coatingpermittivity from the computer program, or from other memory 20. Thecomputer program directs the processing unit 18 to produce the estimatedcomponent transmission loss of radar signal through the desiredcomponent 66, where the processing unit may access the calculations anddata for this estimation from the memory 20, or from the computerprogram. The computer program directs the output device 22 to presentone or more of (a) the estimated component transmission loss, (b) themaximum component transmission loss, (c) the suggestion of a recommendedcoating criterion, a recommended substrate criterion, or both, (d) thegraph illustrating the estimated component transmission loss against asubstrate criterion, (e) the graph illustrating the estimated componenttransmission loss against a coating criterion, or other information asmentioned above.

This description has represented the loss of radar signal through acomponent as a transmission loss, but there are alternative ways toexpress the same concept. For example, reduced reflection or absorptionare alternative ways of expressing the same concept, or increasedpermittivity. Reference has been made to radar frequency, and this canbe expressed as wavelength with different values but the same concept.

While at least one exemplary embodiment has been presented in theforegoing detailed description, it should be appreciated that a vastnumber of variations exist. It should also be appreciated that theexemplary embodiment or exemplary embodiments are only examples, and arenot intended to limit the scope, applicability, or configuration of thedisclosure in any way. Rather, the foregoing detailed description willprovide those skilled in the art with a convenient road map forimplementing the exemplary embodiment or exemplary embodiments. Itshould be understood that various changes can be made in the functionand arrangement of elements without departing from the scope of thedisclosure as set forth in the appended claims and the legal equivalentsthereof.

What is claimed is:
 1. A method of estimating a transmission loss ofradar signal through a component, the method comprising the steps of:receiving a desired substrate criterion of a desired substrate, whereinthe component comprises the desired substrate and a desired coating,wherein the component is a component of a motor vehicle, and wherein thedesired coating comprises coating layers selected from at least one of agroup of a primer, a basecoat, a clearcoat, a sealer, a surfacer, anadhesion promotor, a midcoat, and combinations thereof; receiving adesired coating criterion of the desired coating; receiving a coatingcriterion value, wherein the coating criterion value quantifies thedesired coating criterion; measuring a plurality of known coatingpermittivities for the desired coating criterion at a plurality ofdifferent coating criteria values; estimating a desired coatingpermittivity for the desired coating from the plurality of known coatingpermittivities measured at the plurality of different coating criteriavalues, and with the coating criterion value; producing an estimatedcomponent transmission loss of radar signal through the component;determining if the estimated component transmission loss of radar signalis less than a maximum component transmission loss; suggesting arecommended criterion, wherein the recommended criterion reduces theestimated component transmission loss, and wherein the recommendedcriterion is selected from at least one of a group of a substratethickness, a substrate material, a basecoat thickness, a basecoatpigment loading, a primer thickness, and a combination thereof; andplotting the estimated component transmission loss in athree-dimensional plot against the substrate criterion and the coatingcriterion.
 2. The method of claim 1, further comprising: producing thecomponent with the recommended criterion.
 3. The method of claim 1,further comprising: producing the component with the recommendedcriterion, where the recommended criterion is selected from the group ofthe substrate thickness, the substrate material, and combinationsthereof.
 4. The method of claim 1, wherein receiving the desired coatingcriterion comprises receiving a type of an effect pigment flake in thebasecoat, and wherein quantifying the desired coating criterioncomprises selecting an effect pigment flake concentration in thebasecoat.
 5. The method of claim 4, wherein receiving the desiredcoating criterion further comprises selecting an aspect ratio of theeffect pigment flake.
 6. The method of claim 1, further comprising:interpolating the desired coating permittivity for the desired coatingfrom the plurality of known coating permittivities measured at theplurality of different coating criteria values.
 7. The method of claim1, further comprising making a mathematical model relating the pluralityof known coating permittivities to the plurality of different knowncriteria values for the desired coating criterion, and entering thecoating criterion value into the mathematical model to estimate thedesired coating permittivity.
 8. The method of claim 1, whereinreceiving the desired substrate criterion comprises receiving a desiredsubstrate material.
 9. The method of claim 1, wherein: producing anestimated component transmission loss of radar signal through thecomponent further comprises producing the estimated componenttransmission loss of 77 giga hertz (GHz) brand radar through thecomponent.
 10. The method of claim 1, wherein suggesting the recommendedcriterion further comprises suggesting a desired substrate thicknessthat reduces the estimated component transmission loss.
 11. The methodof claim 1, wherein suggesting the recommended criterion furthercomprises: producing a graph illustrating the estimated componenttransmission loss plotted against the substrate criterion.
 12. Themethod of claim 1, wherein suggesting the recommended criterion furthercomprises: producing a graph illustrating the estimated componenttransmission loss plotted against the coating criterion.
 13. The methodof claim 1, further comprises: suggesting a recommended radar frequencyfor reducing the estimated component transmission loss.
 14. A computerreadable medium that is tangible, comprising: a computer program,wherein the computer program is configured to; receive a desiredsubstrate criterion of a desired substrate, wherein a componentcomprises the desired substrate and a desired coating, and wherein thedesired coating comprises coating layers selected from at least one of agroup of a primer, a basecoat, a clearcoat, a sealer, a surfacer, anadhesion promotor, a midcoat, and combinations thereof; receive adesired coating criterion of the desired coating; receive a coatingcriterion value, wherein the coating criterion value quantifies thedesired coating criterion; receive a plurality of known coatingpermittivities for the desired coating criterion at a plurality ofdifferent coating criteria values; estimate a desired coatingpermittivity for the desired coating from the plurality of known coatingpermittivities measured at the plurality of different coating criteriavalues and with the coating criterion value; produce an estimatedcomponent transmission loss of radar signal through the component;determine if the estimated component transmission loss of radar signalis less than a maximum component transmission loss; suggest arecommended criterion, wherein the recommended criterion reduces theestimated component transmission loss, and wherein the recommendedcriterion is selected from at least one of a group of a substratethickness, a substrate material, a basecoat thickness, a basecoatpigment loading, a primer thickness, and a combination thereof; and plotthe estimated component transmission loss in a three-dimensional plotagainstthe substrate criterion and the coating criterion.
 15. Thecomputer readable medium of claim 14, wherein: the computer programcomprises a mathematical model that relates a plurality of known coatingpermittivities to a plurality of different known criteria values for thedesired coating criterion; and wherein the computer program isconfigured to estimate the desired coating permittivity by entering thecoating criterion value into the mathematical model.
 16. The computerreadable medium of claim 14, wherein: the computer program is configuredto suggest a desired substrate thickness that minimizes the estimatedcomponent transmission loss.
 17. The computer readable medium of claim14, wherein: the computer program is further configured to produce athree-dimensional plot illustrating the estimated component transmissionloss plotted against the desired coating criterion and the desiredsubstrate criterion.